Autism expert Simon Baron-Cohen has a theory that the autistic male shows evidence of a brain that is too male for his own good, the autistic personality being male to the extreme, evidencing exaggerated male characteristics. For example, the autistic is not just a little dissociated and abstract, but very dissociated and abstract. Baron-Cohen suggests that exposure to high levels of testosterone in the mother’s womb in combination with an absence of testosterone surges that prune early childhood synapse production that create a right-handed (as opposed to random-handed) person combine to encourage the emergence of autism.
Still enamored of natural selection, medical theorists explore the etiologies, or origins, of conditions and disorders encumbered by a theory structure that supports a narrow, patrifocal point of view. Informed by the fertile, earlier work of Norman Geschwin, Baron-Cohen has noted some of the most important clues to understanding how humans evolved and autism develops, but I don’t think he’s seeing the larger picture.
Autism is an evolutionary condition. Ontogeny reenacting phylogeny, Geschwin and Baron-Cohen’s clues are major interstate intersections on the roadmap of Homo sapien’s unfolding. When navigating across country, we look at the map and then use our eyes to read the signs around us, and then use the signs around us to read the map. We go back and forth between two representative systems while passing through the real world to find our way. To satisfactorily navigate the riddle of how autism emerges, it is necessary to explore both evolution and ontogeny, while paying attention to sexual selection and social structure in society, jumping back and forth, until we can figure out where we’re located in the life of a human being.
There are major intersections in our evolution, as there are major events in our own ontogeny or personal unfolding. A hundred years ago, this perspective was conventional. The Darwinian synthesis of the mid 20th century, accompanied by the cultural capitulation to Social Darwinist perspectives, narrowed orthodox theorizing to a thin band of back roads hypothesizing around an allegiance to the idea of random origins. Understandings informed by shifting scales, for example, comparing biology, society and ontogeny, were considered unproductive and became unfashionable.
Perhaps no single feature of a human being so informs both our evolution and our children’s lives more than the testosterone and estrogen levels of the mother while the child is in the womb. Baron-Cohen understands the influence of testosterone but hasn’t assimilated the repercussions. This feature is one of the major physiological intersections informing the directions we evolve. High testosterone mothers birth low testosterone males and high testosterone females. Low testosterone females create high testosterone males and low testosterone females. Mother’s blood suggests and prescribes social structure, evolutionary trajectories and individual human skill/challenge constellations, simultaneously.
Very few myths are shared by aboriginal tribes on six continents. One central belief is that a woman’s blood possesses more power, more potency than all other magic. No single issue motivates social conservatives more than the compulsion to control a woman’s womb. In the roadmap of human experience, this issue is where the mythic and manifestly real intersect.
Ontogeny recapitulates phylogeny, or reenacts it. Perhaps 150,000 to 50,000 years ago, before the exodus from Africa, there occurred the shift to right-handed males from random-handed males. This shift is the conversion from random-handed, cooperative, neotenous males with two hemispheres the same size to the more aggressive, hierarchical, right-handed males with the left hemisphere slightly reduced in size. I would suggest this facility-with-language anomaly evidenced itself at puberty. As the feature of non-gestural, verbal articulate behavior was encouraged by women choosing men displaying the trait, they chose non-neotenous males, accelerating or manifesting adult features into the childhood of descendants rather than prolonging infant features into adulthood as had been done in matrifocal societies for perhaps hundreds of thousands of years. Consider that the testosterone surge we see in early childhood is a re-enactment of its emergence as a feature around puberty perhaps a hundred thousand years before, the process having appeared earlier in ontogeny with every passing generation. What we are observing in early childhood with synapse pruning in right-handers is the repercussion of the emergence of a trait, selection for that trait and the absorbing of that feature by the species.
In other words, the contemporary (soon-to-be right-handed) infant/toddler testosterone surge might be an echo of puberty from before our African ancestors hit the road.
It has been suggested that a split brain was necessary to talk because the tongue is in the center of the body. Gestural communication would rely upon noncompeting hemispheres controlling one side of the body at any time. When both brain hemispheres sought to control the tongue, stuttering was the inevitable result. (A high percentage of stutterers are left-handed.) By selecting males that did not stutter when talking, females were selecting men with single hemispheric control of speech.
Why females were already talking when the process of speech production began for men I’ll discuss in another entry.
What might reverse that process that compels the emergence of males having difficulty speaking? On this roadmap we are exploring, what might coerce traffic to move in the opposite direction? What might influence changes in the amount of testosterone in a mother’s blood?
See causes of autism 1, 2 and 3 in this section.
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Proceed to author’s FREE book download on this subject (The book is called Evolution, Autism and Social Change). 10 minute introductory video here.
Andrew Lehman on 10/20/09 in Evolution, featured | No Comments | Read More
